1. Field
Aspects of embodiments of the present invention relate to a touch screen panel and, more particularly, to a flexible touch screen panel.
2. Description of the Related Art
A touch screen panel is an input device capable, for example, of inputting a user's instruction by selecting instruction contents displayed on a screen of an image display device, or the like, with, for example, a human hand or an object. To this end, the touch screen panel may be provided on a front surface of the image display device to convert a contact position directly contacted by the human hand or the object into an electric signal. The instruction contents selected at the contact position is then recognized as an input signal. Since the touch screen panel may be substituted for a separate input device that operates by being connected to the image display device, such as a keyboard or a mouse, application fields thereof have been gradually extended.
Implementation types of touch screen panels include resistive type touch screen panels, photosensitive type touch screen panels, capacitive type touch screen panels, and the like. Among them, the capacitive type touch screen panels operate by sensing a change in capacitance formed between conductive sensing patterns and neighboring other sensing patterns or a ground electrode, or the like, when a human hand or an object contacts the touch screen panel, thereby converting a contact position into an electric signal.
A touch screen panel as described above may be attached to an outer surface of the image display device, such as a liquid crystal display device or an organic light emitting display device, as part of a product manufacturing process. Therefore, the touch screen panel may benefit from characteristics such as high transparency and a thin profile. In addition, flexible image display devices have been recently developed. As such, touch screen panels attached to the flexible image display may also benefit from being flexible.
However, in order to form sensing patterns for implementing a touch sensor in the capacitive type touch screen panel, processes such as thin film forming, pattern forming, or the like, may be used. Therefore, the capacitive type touch screen panel may require properties such as high heat resistance and chemical resistance, or the like. However, capacitive type touch screen panels (that use, for example, sensing patterns or the like) have been formed on glass substrates. Since glass substrates should have sufficient thickness (for example, thickness of a predetermined value or more) to function properly as substrates (for example, be capable of being carried in the manufacturing process), characteristics such as sufficient thinness and flexibility may not be satisfied.
In addition, sensing patterns of capacitive type touch screen panels have been made of indium tin oxide (ITO), but metal oxide films such as ITO may be easily damaged by warping or other physical stresses. Further, high deposition temperature and/or high annealing temperature may be needed to provide proper conductivity of the metal oxide film. However, adhesion of the metal oxide film to a substrate in which moisture is easily absorbed, such as a plastic or organic substrate that is used as a flexible substrate (for example, a polycarbonate substrate), may deteriorate.
In addition, a polarizing plate may be attached to the outer side of the image display device in order to improve outdoor visibility or the like. When a touch screen panel is attached to an upper portion of the image display device, the polarizing plate may be attached to an outer surface of the touch screen panel. Further, the polarizing plate and the touch screen panel may go through processes in which they are each separately manufactured and then bonded or assembled together. However, this may lead to problems in the touch screen panel, such as an increase in overall thickness, a reduction in process efficiency, a reduction in yield, or the like.